Polygamy

n.
  1. The having of a plurality of wives or husbands at the same time; usually, the marriage of a man to more than one woman, or the practice of having several wives, at the same time; -- opposed to monogamy; as, the nations of the East practiced polygamy. See the Note under Bigamy, and cf. Polyandry.
  2. (Zoöl.) The state or habit of having more than one mate.
  3. (Bot.) The condition or state of a plant which bears both perfect and unisexual flowers.